Jerry

I really appreciate your posts on installing a Fitech in one of your coaches - comments like this plus the fact that I was going to have to bear the cost of buying a rebuilt Quadrajet to finish off my coach were what prompted me to go the Fitech route.

Full disclosure - although I have rebuilt old cars and motorcycles, my mechanical knowledge of anything more modern that the mid-60s is sorely lacking. But rest assured - I am having the FI installed by a professional.

I specifically chose the 600 based on the understanding that the FI's computer module would control the spark advance of my "pointless" distributor. Do I understand that according to Fitech, most of their customers stick with good old mechanical and vacuum spark control? And if this is the case, any reason why? Is this what you did as well?

Thanks

Gordon
1976 23' Norris Upfit
Montreal West, Quebec, Canada

gibsongo wrote on Sat, 28 May 2016 14:04

Jerry

I really appreciate your posts on installing a Fitech in one of your coaches - comments like this plus the fact that I was going to have to bear the cost of buying a rebuilt Quadrajet to finish off my coach were what prompted me to go the Fitech route.

Full disclosure - although I have rebuilt old cars and motorcycles, my mechanical knowledge of anything more modern that the mid-60s is sorely lacking. But rest assured - I am having the FI installed by a professional.

I specifically chose the 600 based on the understanding that the FI's computer module would control the spark advance of my "pointless" distributor. Do I understand that according to Fitech, most of their customers stick with good old mechanical and vacuum spark control? And if this is the case, any reason why? Is this what you did as well?

Thanks

Gordon
1976 23' Norris Upfit
Montreal West, Quebec, Canada

According to FiTech documentation, timing control cannot be used with an HEI Distributor. It is not clear to me if there is a distributor that could be substituted on an Olds engine to allow computer control by the FiTech EFI. If it cannot control spark on the 455 or 403, then I would see no reason to get the 600 hp efi unit. The 400 hp unit would be adequate and costs less. I have also seen references that you can pin the mechanical advance plate and get the HEI to work. I would think FiTech would not say HEI was not supported if this were possible? Looks like you could install an MSD ignition system and get this to work.

However, They only have a 3x3 table to control spark so I would be concerned if you get much benefit to letting the EFI unit control spark. I'm guessing you can command Spark Advance (SA) for 9 points and it then extrapolates those into a spark curve. Maybe slightly better than an HEI curved distributor but not by much. Most early GM TBI EFI systems had up to 12 x 16 cells for SA (more for higher RPMs than in our applications).

Interesting to see how computer controlled spark actually works/performs for our application?